An investor group led by Yoshiaki Murakami told JAFCO in meetings early this month that they had amassed nearly 15% of its shares and suggested that there is a possibility of increasing their stake to 51%, the firm said in a regulatory filing.

The Murakami group also requested that JAFCO buy back shares worth about 50 billion yen ($374.76 million), or a third of its market value, the filing said.

A representative for the group's main fund, which is called City Index Eleventh, declined to comment when contacted by Reuters and asked about possibly raising its stake to 51%.

Given the threat of a takeover, JAFCO's board on Monday decided to introduce countermeasures, including an option to issue stock warrants to existing shareholders which would dilute the stake held by the Murakami-related parties, when required conditions are met.

A poison pill that targets a specific bidder - called an emergency poison pill in Japan - was first successfully employed in 2020 by Toshiba Machine, renamed Shibaura Machine, in its fight against Murakami.

($1 = 133.4200 yen)

(Reporting by Makiko Yamazaki; editing by Jason Neely)